Abstract: A magnetic plate retention system especially suitable for use in retaining a lithographic plate material to a conventional plate cylinder utilizes one of more elongated retention devices selectively positioned anywhere along the outer circumferential surface of the plate cylinder parallel to the axis of rotation of the cylinder. The retention devices are applied, removed, and retained with an application/removal assembly.

Abstract: A magnetic plate retention system especially suitable for use in retaining a lithographic plate material to a conventional plate cylinder utilizes one of more elongated retention devices selectively positioned anywhere along the outer circumferential surface of the plate cylinder parallel to the axis of rotation of the cylinder. The retention devices are applied, removed, and retained with an application/removal assembly.

Abstract: A printing plate is clamped to a plate support by providing the plate support with a magnetic surface and laying a printing plate having opposite edges on that surface. Then, a first strip-like ferromagnetic blade clamp is deposited on the plate so that the first blade clamp is adjacent and parallel to one edge of the plate and a second strip-like ferromagnetic blade clamp is deposited on the plate so that the second blade clamp is adjacent and parallel to the opposite edge of the plate. The magnetic attraction of the blade clamp to the support surface enables the blade clamps to releasably clamp the printing plate to the support surface. Dispensing mechanisms for depositing the blade clamps on, and removing them from, the support surface are disclosed. The invention has particular application to releasably clamping superimposed donor and receptor sheets to the plate cylinder of proofing apparatus.

Abstract: Dimensional inconsistencies between a proof and an image to be overlaid thereon is avoided by subjecting both the proof image and the overlay image to the same heat treatment, thereby ensuring that both images undergo the same degree of shrinkage.

Abstract: Cleaning apparatus for lithographic printing plates includes a rotating elastomeric roller that contacts imaged plates, which are typically (although not necessarily) carried on a rotary cylinder, at a velocity different from the velocity (if any) of the plate. The roller may spin in the direction of, or opposite to, that of the cylinder and at substantially different speed. Typically, the apparatus is mounted proximate to the cylinder, circumferentially adjacent to the imaging system, and is retractable so as to be selectively engaged when imaging is complete. The apparatus may include, in addition to or in lieu of the elastomeric roller, a second retractable cleaning member for rubbing the imaged plate with a cleaning fluid. The second cleaning member may be an elongated cartridge having an absorbent towel exposed along one face thereof. A cleaning fluid is dispensed onto the towel by, for example, a spraying device. The cartridge is then extended to urge the towel against the printing plate as it rotates.

Abstract: Cleaning apparatus for cleaning a lithographic plate mounted to a rotary plate cylinder comprises an endless belt having a segment extending close to and substantially parallel to the cylinder. Plate cleaning pads are mounted to the belt all along the belt and a motor advances the belt along the cylinder. When cleaning, a bladder is caused to inflate thereby pressing the belt segment and cleaning pads thereon against the plate mounted to the plate cylinder while the cylinder rotates.

Abstract: An ink jet image transfer lithographic apparatus is coupled to a source for supplying graphics and textual material to an ink jet printhead. The ink jet printhead melts a hydrophobic solid ink and sprays the ink onto a lithographic plate in a predetermined pattern. The solid ink solidifies upon contact with the plate. The plate is then mounted in a lithographic press for lithographic printing. As an alternative, the ink jet printhead may be mounted in a lithographic press for imaging a lithographic plate mounted in the lithographic press or for spraying ink directly onto the plate cylinder of the press. A succession of lithographic plates may be provided around the plate cylinder of the lithographic press and each plate discarded after use, leaving a clean plate on the plate cylinder.

Abstract: In the dot matrix printer disclosed herein, a multicolor ribbon is shifted to bring different colored stripes in alignment with the nosepiece of a dot matrix printhead by means of cup-like ribbon guide members journaled on either side of the nosepiece. Each guide member provides, in its periphery, an arcuate slot through which the ribbon can freely slide as the printhead traverses. A stepping motor is coupled to the guide members for rotating them so as to selectively bring a stripe of desired color into operative position.

Abstract: A printer having at least one reciprocally mounted printing member controlled to impact against a printing surface by selective energization of an associated printing driving member. The forward end of the member is guided by a bearing. Ink from a supply source is directed to the printing member near the forward end of the printing member whereby the ink is drawn into the region between the guide hole in the printing member guide bearing and the periphery of the printing member to be moved to the region in front of the forward tip of the printing member whereby activation of the driving member abruptly moves the printing member in the forward printing direction causing the ink deposited upon the tip of the printing member to be urged toward and against the ink receiving medium to transfer the ink to the ink receiving medium. A group of printing members may be used to print in this manner to collectively form characters, symbols, and even graphic patterns.

Abstract: In the dot matrix printer disclosed herein, a multicolor ribbon is shifted to bring different colored stripes in alignment with the nosepiece of a dot matrix printhead by means of cup-like ribbon guide members journaled on either side of the nosepiece. Each guide member provides, in its periphery, an arcuate slot through which the ribbon can freely slide as the printhead traverses. A stepping motor is coupled to the guide members for rotating them so as to selectively bring a stripe of desired color into operative position.